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The structural and functional essentiality of the N‐terminal α‐helix in the phospholipase A2 of the Taiwan banded krait
Author(s) -
Chang LongSen,
Chang ChunChang,
Wu PeiFung
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700202341
Subject(s) - helix (gastropod) , enzyme , active site , phospholipase a2 , recombinant dna , residue (chemistry) , binding site , stereochemistry , chemistry , biochemistry , biology , ecology , snail , gene
In order to identify the structural and functional essentiality of the N‐terminal α‐helix of Bungarus multicinctus PLA2 for its enzymatic activity, comparative studies of the biochemical properties of native and recombinant PLA2 were made. It was found that the appearance of a Met residue preceding the N‐terminus Asn‐1 of the recombinant protein appreciably affected PLA2 activity and the hydrophobic character of the ANS‐binding site. Additionally, the charged state and the hydrophobicity of the molecular surface changed as well. However, removal of the N‐terminal Met‐1 from the recombinant PLA2 resulted in the production of a fully active PLA2, whose biochemical properties were indistinguishable from those of the native enzyme. These observations, together with the findings that the helical wheel plot of the N‐terminal α‐helix showed distinct hydrophobic and hydrophilic faces and that the ANS‐binding site was the active site of PLA2 enzymes, suggest that the hydrophobic face of the N‐terminal α‐helix in native PLA2 should be in the interior of the enzyme molecule for binding with ANS and the phospholipid/substrate.